Non-repeat and signal assurance mechanism for printing telegraph apparatus



May 22, 1962 F. c. MOEBIUS 3,036,155

NON-REPEAT AND SIGNAL ASSURANCE MECHANISM FOR PRINTING TELEGRAPH APPARATUS Filed July 11, 1960 3 Sheets-Sheet 1 ION org N FIG.

INVENTOR FREDERICK C. MOEBIUS FIG. 3

ATTORNE May 22, 1962 F. c. MOEBIUS 3,036,155

NON-REPEAT AND SIGNAL ASSURANCE MECHANISM FOR PRINTING TELEGRAPH APPARATUS Filed July 11, 1960 5 e ts-Sheet 2 INVENTOR FREDERICK C. MOEBIUS BY @F ATTORN Y May 22, 1962 F. c. MOEBIUS 3,036,155

NON-REPEAT D SIGNAL ASSURANCE MECHANISM FOR FRI TELEGRAPH APPARATUS Filed July 11, 1960 5 -S eet 5 INVENTOR FREDERICK C. MOEBIUS BY @Q.

ATTOR EY States ware Filed July 11, 1960, Ser. No. 41,870 5 Claims. (Cl. 178-17) This invention relates to telegraph transmitters in general and in particular to a non-repeat mechanism in combination with a subsequent signal assurance mechanism for keyboard controlled telegraph transmitters.

Keyboard controlled telegraph transmitters of the type disclosed in US. Patent No. 1,595,472, granted August 10, 1926, to H. L. Kru-rn and Patent No. 1,766,713 granted June 24, 1930, to E. E. Kleinschmidt, which patents are hereby incorporated by reference as if fully reproduced herein, generally include a plurality of keys operable to set a plurality of code bars in accordance with a code, e.g., the well known five unit Baudot code. Operation of any key is also efiective to operate a control instrumentality or universal bar, such as bail 62 or clutch control bar 410 shown in the incorporated patents, respectively, which is operable to engage a clutch to transfer rotative power, provided by a motor, to a set of cams which, through intermediate members, sense the permutative setting of the code bars. Signal producing means, one or more sets of contacts, are selectively opened and closed by the rotating cams through other intermediate members to produce a signal in accordance with the permutative setting of the code bars and corresponding to the character represented by the operated key.

Since the signal producing means operate at a fixed speed determined, of course, by the speed of rotation of the motor, usually at. speeds to produce 360, 450 or 600 operations per minute, and since to produce a signal in response to every depression of a key the number of operations of the keyboard per minute must not exceed the maximum possible number of operations per minute of the signal producing means, means must be provided to preclude the transmission of more than one signal upon the depression of a key for a time greater than that required by the transmitter to produce and transmit one signal, otherwise, the transmitter could possibly transmit the same signal more than once upon a single key depression. The operation or depression of a key for a greater time than required to transmit a single signal shall be referred to hereinafter as sustained operation or depression. And, it will be appreciated, that since the keyboard, in all likelihood, will be operated at as many different speeds as there are operators, the relative timing between the speed of operation of key and the signal producing means will be compounded.

The limitation of the transmission of a single signal upon the sustained operation of a key is accomplished by the employment of instrumentalities, known in the art as non-repeat means, which disengage the clutch after a single cycle of operation of the signal producing means and, hence, operate the clutch in single cycle fashion. The provision of the non-repeat means, however, frequently introduces another problem. Operators are generally said to operate the keys at 240, 300 or occasionally as high as 450 operations per minute (operations per minute are converted to words per minute by dividing by 6) however, what is really being said is that the operator averages such speeds over a given period. And an operator who is averaging only 240 operations per minute, or 40 words per minute, can, upon the successive operation of two keys with fingers on opposite hands, attain a relative or instantaneous speed of 2100 IQQ operations per minute or 350 words per minute. Upon such successive key operation, many presently known non-repeat means can, upon becoming eifective after the transmission of the first signal in response to the first operated key, preclude the transmission of the second signal in response to the second operated key thereby causing a skip or omission of a wanted character or signal. Ovbiously, the possibility of such an ommission is extremely undesirable.

Accordingly, the object of this invention is to provide, in combination, a non-repeat mechanism for precluding the repetitious transmission of a signal upon the sustained operation of a key and a second signal assurance mechanism for assuring the transmission of a second signal in the event of the operation of a second key upon the completion of the transmission of the first signal but before the non-repeat means becomes effective to preclude initiation of another cycle of said cyclically operable means.

A feature of the invention resides in the addition of a non-repeat means for limiting the operation of a cyclically operable means to a single cycle of operation upon the sustained operation of a key and a control lever engageable by said non-repeat means for assuring the initiation of a second cycle of operation of the cyclically operable means in the event of the operation of a key substantially upon completion of a cycle by said cyclically operable means but before the non-repeat means becomes effective to preclude initiation of another cycle of said cyclically operable means.

A more complete understanding of the invention may be obtained from the following detailed description when read in conjunction with the appended drawings in which:

FIG. 1 is a plan view of the transmitter;

FIG. 2 is an irregular sectional view taken substantially along the line 22 shown in FIG. 1 and in the direction of the arrows;

FIG. 3 is an irregular sectional view taken substantially along the line 3-3 shown in FIG. 2 and in the direction of the arrows;

FIG. 4 is an enlarged fragmentary View, taken from FIG. 2, showing the illustrated elements in greater detail;

FIGS. 5 through 8 are fragmentary views, taken from FIG. 2, showing the positions the illustrated elements occupy during an operation sequence; and

FIG. 9 is a sectional view taken along the line 99 shown in FIG. 5 with some elements shown in phantom.

Referring now to the drawings and more particularly to FIG. 1, there is shown a plurality of key levers ll, corresponding to the key levers 13 of keys 17 shown in the firs-t mentioned incorporated patent or key bars 399 shown in the second mentioned incorporated reference, which span a plurality, five in number, of code bars 12 and a control instrumentality or universal bar 13. The bars are supported for longitudinal movement, the right end of each bar being provided with a hook like portion 15, as may be seen in FIG. 2, which encircles partially a shaft 17 and the left end, it will be understood, being supported in any suitable manner, as for example, by the roller 23 shown in FIG. 2 of the incorporated patent of H. L. Krum.

In the manner well known in the art, the code bars 12 are adapted to be set permutatively in accordance with the familiar five-unit Baudot code. Upon the depression of any key representing a character, the associated key lever 11 is moved downwardly into engagement with the cam lugs 14 of the code bars 12, and the code bars corresponding to the elements which are marking in the character, as represented by the Baudot code, are cam-med to the right; the code bars which correspond to the elements which are spacing remain to the left.

Mounted pivotally on the universal bar 13, FIG. 4,

- are a non-repeat lever 20 and an universal bar extension stretched between spring hooks 3 4 and 35 formed on the extension and universal bar, respectively, and the counterclockwise movement of the extension is arrested by a stud 37 secured, suitabl to the universal bar.

A generally U-shaped bracket 40, referring again to FIG. 1, having leg portions 41 and 42, is secured, as for example by welding, to the frame 44 and supports shafts 46, 47 (FIG. 2), 48 and 49. Mounted rotatably on the shaft 46 are an integrally formed gear 50 and toothed member 51; the gear- 59 is meshed in driving engagement with a gear 54 secured to a motor shaft 55 of a motor, motor 6 of the incorporated patent of H. L. Krum. Also mounted rotatably on the shaft 46 is a cam sleeve 58 comprising a plurality of cams; bail reset cam 59, flutter cam 60, helically arranged transmitter earns 61 to 65, inclusive, and a stop-start cam-66. The flutter cam'60 is provided with seven apices, one for each of the five elements of the Baudot code plus the start and stop elements and each of the five transmitter cams and the stop-start cam are provided with one peripheral indentation; the six indentations are arranged helically in the manner wellknown in the art. A clutch member 69, formed integrally on the cam sleeve 58, is provided with a projection 70 which supports a shaft 71 and mounted pivotally on the shaft 71, is a clutch pawl 73, FIG. 2, which is urged'clockwise by a spring 74 into engagement with the toothed member 51.

A generally U-shaped bail 76, FIGS. 1 and 2, is mounted pivotally on the shaft 47 and is provided with a blade 77, a stop projection 78, 'a stud 79 and a cam follower portion 81 The bail 78 is urged counterclockwise by a spring 89 and the counterclockwise movement of the bail is normally arrested by the universal bar extension 21 which maintains the bail in the position shown in FIG. 2 with the stop projection 78 engaging and pivoting the clutch pawl 73 counterclockwise out of engagement with the toothed member 51.

A plurality of earn followers 81 to 85, inclusive (FIG. 1), and start-stop cam follower 86 are urged by individual springs 88 (FIG. 2) into cooperative engagement with the helically arranged transmitter cams 61 to 65, inclusive, and start-stop cam 66, respectively. The

' cam followers 81 through 85 are provided at their left ends, as may be seen readily in FIG. 1, with code bar sensing arms 91 to 95, inclusive. The arms 91 to 95 inclusive, sense whether or not the code bars have been moved to the right, if a bar has been moved to the right "downward movement of the associated arm is blocked and counterclockwise movement of the cam follower is precluded upon the presentation of the identation for-med in the associated transmitter cam to the cam follower. It will be noted that the left end of arm 96, FIG. 1, of the start-stop cam follower 86 is shorter than the other arms 91through 95 for a reason to become apparent later.

H A flutterlever 161 and a detent arm 102, FIG. 2,

I 1 having a stabber portion 103 are mounted pivotally-on the shaft 49 and are urged counterclockwise by individual springs 104 and 105, respectively. The lever 101 is urged into cooperative engagement with the flutter cam .60and mounted pivotally on the flutter lever 161, is a [transfer member 163 which is provided with an opening 169 and a pair of abutments 116 and 111.

' Mounted pivotally on the shaft'48, as maybe seen 116 which is received in .the opening 109 formed in the transfer member 1118. The bail 114 is urged countertained in a housing 135. The upper end of the link 132 is connected to the stem 136 of a T-shaped contact lever 133 which engages pivotally at 140 a fulcrum member 141. The fulcrum member 141 cooperates with a V- shaped notch 143 formed in a bracket 144 mounted in the housing 135. A spring 146, stretched between the bracket 144 and the fulcrum member 141, urges the fulcrum memher in a clockwise direction about the V-shaped notch 143 and urges the contacts 151 and 152 in engagement with their associated contacts 153 and 154. Contacts 151 and 153 comprise a set of spacing contacts and contacts 152 and 153 comprise a .set of marking contacts. Since the pivotal:connection between the fulcrum member 141 and the T-shaped contact lever 138 is located centrally ofthe lever, a balanced or equal pressure is exerted with respect to each of the sets of contacts and the T- shaped contact lever is said to be floating. In actual practice, the T-shaped lever 138-will be operated by the link .132 to such a position that one set of contacts will be closed.

Referring now to'FIG. '3, there is shown a member 157, mounted pivotally on the shaft 47, adapted to pivot with the bail 7 6 and which member is provided with an indentation 158, encircling a reduced portion .160 of the stud 79, and an upwardly and rightwardly directed portion 161. Also, mounted pivotally on theshaft 47 is a control lever 164 which includes an abutment portion 165. Spring .168 is stretched between the control lever 164 and the arm portion 161 and is sufliciently strongto pivot the control lever clockwise upon clockwise movement of the bail 76 and is operable to permit relative independent movement between the lever and bail.

Operation of the Non-Repeat Means The operation of the non-repeat means for limiting the transmitter to the transmission of a single signal representing a single character upon the sustained operation of a key will now be set forth. It will be assumed that the above described instrumentalities occupy the positions shown in FIG. 2 and that the gears 50 and '54 and toothed member 51 are constantly rotating. Upon the operation of a key representing a character, the associated key lever 11 is moved downwardly into engagement with the cam lugs 14 of the code bars 12 and universal bar 13. The universal bar '13, upon the operation of any key lever, is invariably moved to the right and the code bars 12 which are marking in the character, as represented by the Baudot code, are moved to the right and the code bars are said to be set permutatively. Upon the rightward movement of the universal bar 13, the abutment 165 of the control lever 164 engages the laterally directed portion29 of the non-repeat lever 21 and pivots the nonrepeat lever counterclockwise as may be seen in FIG. 8 and, during a major portion of the rightward movement of the universal bar, the universal bar extension .21 maintains the bail 7.6 in the position shown in FIGS. 2 and 5. Continued rightward movement of the universal bar 13 moves the extension 21 out from under the blade 77 of the bail 76 and the spring 89, as may be seen in FIG, 6, pivots the bail countenclockwise. The bail through the stud 79 pivots the control lever 164 counterclockwise and the abut- 'ment portion 165 is moved'downwardly out of abutting engagement with the laterally directed portion 29 and the spring 28 pivots the non-repeat lever 20 clockwise moving the laterally directed portion '29 on top of the abut moot-165.

As thebail 76 was pivoted counterclockwise, the stop projection '78 was moved out of engagement with the clutch pawl 73 and the spring 74 pivoted the pawl clockwise into engagement with the toothed member 51 and rotative power was transferred to the cam sleeve 58 and a cycle of operation was initiated. Upon the initial rotation of the cam sleeve 58, the indentation formed in the stop start cam 66 is presented to the start-stop cam folower 86 having the shortened left-hand portion as shown in FIG. 1, and the cam follower 86 under the influence of its associated spring 88 is pivoted counterclockwise (FIG. 2) about the shaft 47. Since the left-hand portion of the cam follower is shortened, the portion cannot engage any code bars and counterclockwise movement of the startstop cam follower always occures upon the presentation of the indentation of the stop-start cam to the follower 86. The right end 120 of the stop-start cam follower 86, upon counterclockwise movement of the cam follower 86, engages the cam follower sensing blade 115 and pivots the oscillatable bail 114 clockwise against the tension exerted by spring 119. Through the interconnection between the bail 114 and the transfer member 108, projection 116 being received in opening 189', the transfer member is pivoted counterclockwise and, upon continued rotation of the selector cam sleeve 58, an apex of the flutter cam 60 engages the transfer lever 101 and pivots the lever and the transfer member clockwise moving the abutment 110 of the transfer member into engagement with the abutment 124 of the rocker member 122. The rocker member 122 is pivoted clockwise about the shaft 48, in the direction of the spacing arrow 170, into a spacing position and is detented in the spacing position by the engagement of the stabber portion 103 with the notch 128. The link 132 is moved downwardly upon the movement of the rocker member 122 into the spacing position and the T- shaped contact lever is pivoted clockwise about the pivotal connection 140 and the set of spacing contacts 151 and 153 is closed, producing thereby a start impulse.

Upon continued rotation of the cam sleeve 58, the helically arranged indentations of the cams 61 to 65, inclusive, are presented sequentially to the cam followers 81 to 85, inclusive. The code bars 12 which are spacing and remain to the left and do not block the left-hand ends of the cam followers, such as end 94 as shown in FIG. 2, and the cam followers fall into the indentations as did the start-stop cam follower 16 and a spacing signal is produced by the closure of contacts 151 and 153. However, upon the presentation of the indentation of a transmitter cam to a cam follower whose associated code bar 12 is marking, i.e., moved to the right, the code bar will block the downward movement of the lefthand code bar sensing arm, for example, code bar 95 as shown in FIG. 2 and the cam follower is not permitted to fall into the indentation formed in the transmitter cam. The spring 119 pivots the oscillatable bail 114 counterclockwise which in turn pivots the transfer member clockwise and, upon the clockwise movement of the transfer lever 101 by the flutter cam 160, the abutment 111 of the transfer member 108 is moved into engagement with the abutment 125 and the rocker member 122 is pivoted counterclockwise in the direction of the marking arrow 171 into a marking position and is detented in the marking position by the detent arm 102. Counterclockwise movement of the rocker member 122 moves the link 132 upwardly, pivoting the T-shaped contact lever 138 counterclockwise about the pivotal connection 140 and the set of marking contacts 152 and 153 are closed.

Toward the end of the cycle of rotation of the cam sleeve 58, the high peripheral portion 173, FIG. 7, of the bail reset cam 59 engages the cam follower portion 80 and pivots the bail 76 clockwise about the shaft 47 presenting the stop projection 78 for engagement with the pawl 73 and, since the control lever 164 is caught under the nonrepeat lever portion 29, the spring 168 will be elongated and the control lever will remain under the projection 29. The high peripheral portion of the reset cam 59 will be rotated past the cam follower 80 and the spring 89 will again begin to pivot the bail counterclockwise so as to move the stop projection 78 out of the path of the pawl 73 and leave the pawl in engagement with the toothed member 51 leaving the pawl 73 in engagement with the toothed member 51 would effectively initiate a second cycle of operation even though the key has been operated but once. However, since the non-repeat lever 20, upon the movement of the control lever 164 below the laterally directed portion 29, was pivoted by the spring 28 into the position shown in FIG. 7, the counterclockwise movement of the bail 76 will be blocked by the non-repeat lever and the stop projection 78 will be presented for engagement with the pawl 73 and, upon continued rotation of the cam sleeve 58, the stop projection will engage the pawl 73 and move it out of engagement with the toothed member 51 thereby arresting rotation of the cam sleeve. Hence single cycle operation is achieved and only one signal combination will be produced upon the sustained depres sion of any key lever 11.

Operation of the Subsequent Signal Assurance Means It will now be assumed that a first key has been operated and the above described cycle of operation has been initiated and is nearing completion, and it will be further assumed that, at such time during the first cycle of operation that the instrumentalities occupied the position shown in FIG. 7, the operator released the first operated key and depressed a second key with the hand opposite of the one which depressed the first key. The code bars 12 were quickly moved to the left and again to the right, but in a new permutative setting corresponding to the second operated key, and the universal bar 13 and nonrepeat lever 20 were moved to the left and again to the right and occupy the positions shown in FIG. 7. Without the inclusion of the control lever 164, it will be observed that, upon the continued rotation of the reset cam 59, counterclockwise movement of the bail 76 will be precluded by the non-repeat lever 20 in the manner set forth supra and the projection 78 will pivot the pawl 73 out of engagement with the rotating toothed member 51. Thus a second cycle of operation will not be initiated even though a second key has been operated and the code bars 12 have been reset in a new permutative setting.

The inclusion of the control lever 164 however, is effective to initiate a second cycle of operation in response to the depression of the second key. It will again be assumed that the instrumentalities occupy the positions shown in FIG. 7 with the abutment 165 of the control lever 164 being under the laterally extending projection 29 of the non-repeat lever 20. Then, upon the release of the first key, the code bars and the universal bars will be moved to the left and the laterally extending portion 29 will be moved fiom over the control lever 164 and the spring 168 will pivot the control lever clockwise to the position shown in FIG. 8. As the code bars 12 and universal bar 13 are moved again to the right, in response to the operation of the second key, the abutment portion 165 will again engage the laterally directed portion 29 and will again pivot the non-repeat lever 20 counterclockwise, as shown in FIG. 8, and the downward movement of the bail 76 will not be blocked. The spring 89 will again pivot the ball 76 to the position shown in FIG. 6, the projection 78 will not move the pawl 73 out of engagement with the toothed member 51 and a second cycle of operation will be initiated to produce a signal in accordance with the second permutative setting of the code bars 12.

Thus it is seen that upon every rightward movement of the universal bar 13, the control lever 164 is eifec tive to pivot the non-repeat lever 20 counterclockwise and successive cycles of operation will be initiated upon subsequent operations of the keys. However, since the downward movement of the bail 76 is operable through the stud 79 to move the control lever 164 under the laterally directed portion 29 of the non-repeat lever20, the non-repeat is rendered eflective upon the sustained depression of a key and, after the bail 76 has been camrned upwardly by the reset cam 59, the downward movementof the bail is precluded by the non-repeat lever 2ft, as shown in FIG. 7, and only one cycle of operation will be initiated upon the sustained depression of any key lever 11.

The transmitter is also provided with means to permit the desired repeated transmission of a signal upon the single depression of a key, viz., the repeat key lever 176 shown in FIGS. 4 and 8. After the desired key has beenoperated and the code bars 12 set permutatively, the repeat key :lever 176 may be operated and, upon beingoperated, the repeat key lever 176 engages the non-repeat lever 20, as may be seen in FIG. 8, and pivots the lever counterclockwise out of the path of the bail 76. Thus the bail 76, after being pivoted by the reset cam 59'to the position shown in FIG. .7, will be moved by the spring 89 to the position shown in FIG. 6 and repeated cycles of operation of the cam sleeve 58 will be initiated as long as the repeat leveris maintained depressed.

The manner in which the universal bar extension 21 permits an early return of the universal bar 13 to the left upon the release of a depressed key will now be set forth. Referringagain to FIG. 6, it will be noted that after the universal bar 13 and extension 21 have been moved from their initial leftward positions to the right in response to the depression of a key and after the bail 76 has been pivoted counterclockwise to engage the clutch pawl 73 the bail blade 77 is interposed between the extension 21 and the initial position of the extension. Upon release of the depressed key, the extension 21 pivots clockwise about the shaft 24 and permits the .universal bar 13 to be moved to the left under the inthemes of the spring 28 before the bail 76 has been cammed .out of the path of the extension 21. Were the extension 21 an integral part of the universal bar 13, it will be appreciated that the universal bar could not be returned to the left until the bail '76 was cammed to the position shown in FIG. 7, i.e., later in the cycle than is possible with the inclusion of the separate pivoted extension 21. Thus the universal bar extension 21 permits a freer keyboard and makes the release of the keys more responsive to theremoval of the operators" fingers. The earlier movement of the universal bar 13 to the left permits the bar to be prepared for earlier movement to the right in response to a successively depressed key thereby giving a'lighter touch to the keys. It is manifest that the preferred embodiment is merely illustrative of the invention and that many modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is: l

I. In a telegraph transmitter, a plurality of permutatively settable code bars, a plurality of keys each operable to set said code bars permutatively, a universal bar ing means operable to produce a signal in accordance with the permutative setting of said code bars, cyclically operable means operable bythe operation of said universal bar to imitate operation 'of said signal producing means, a non-repeat lever mounted on said universal bar and being operable to limit said cyclically operable operable by and in unison with any key, signal prdducmeans to a single cycle of operation upon the sustained operation of said universal code bar, a latch means on saidnon-repeat lever, a movable assurance means operable to prevent said non-repeat lever from limiting the cyclically operable means, engaging means on said assurance means to engage said latching means to latch said assurance means in a non-effective position, and means carried by said cyclically operable means to move said assurance means from a position'wherein said asisurance means prevents said non-repeat means from limiting the cyclically operable means to a' positionwherein tion, each key operable to'cause a setting of said code bars, a universal bar movable by the operation of any key from an initial position into a secondary position and being maintained in said secondary position during the sustained depression of any key; signal producing means for producing a signal in accordance with the permutative setting of said code bars,'cyclically operable means for operating said signal producing means, a movably mounted bail engaged by said universal barwhen in said initial position and positioned thereby so as to engage and restrain said cyclically operable means against operaion, means for disengaging said hail from said cyclically operable means upon movement of said universal bar to the secondary position, means for returning said bail to said restraining position after release of said cyclically operable means, a non-repeat levenmovably mounted on said universal bar and efiective uponmaintenance of said universal bar in said secondary position to hold said bail upon return thereof to said restraining position to retain said bail in position to again restrain said cyclically operable means from operation and limit the operation thereof to a single cycle, and a spring-urged assurance means effective to engage said non-repeat lever and hold said non-repeat lever out of restraining relation to said bail, a holding .means to hold said assurance means in nonefiective position when said non-repeat lever is effective to hold said bail in the restrained position, and means carried by said cyclically operable means to move said assurance means against the urging of its spring into position to be held by said holding means.

3. In a telegraph transmitter, a plurality of manually operable keys, a plurality of code bars permutatively settable by each of said keys, :1 universal bar movable from i an initial position to a secondary position by any of said keys and restorable to said initial position only upon release of the key signal generating means for generating signals in accordance with the setting of said code bars, cyclically operable means for operating said signal gen crating means, a source of power including a rotating member, a clutch including a pawl normally urged into engagement with said rotating member to connect said power source to said cyclically operable means, a pivotally mounted bail having a latching position and including a projection engageable with said pawl, a universal bar extension mounted pivotally on said universal bar and effective when said universal bar is in'said initial position to engage said bail and maintain said bail in said latching position and said projection in engagement with said'pawl to withhold said pawl from engagement with said rotating member, said universal bar extension being disengageable from said bail 'by movement of said universal bar into said secondary position, means for pivoting said bail out of said latching position upon disengagement a cyclically operable means while said universal bar remains in said secondary. position, an assurance means operable to engage said non-repeat lever'and to pivot said nonrepeat lever against the urging of its spring out of blocking relationship with said bail, urging means to move said assurancemeans to a position to engage said non-repeat lever, means operable by said bail to move said assurance means to a position whereinit is inefiective to pivot said non-repeat lever, and a holding means on said non-repeat lever to hold said assurance means against the urging of said urging means while said universal bar is in a secondary position.

4. In a telegraph machine having a cyclically operable selector mechanism normally held from cyclic operation by having its associated clutch means disengaged, a plurality of key levers, a plurality of code bars permutatively set by each of said key levers, a universal bar movable from an initial position to a secondary position by operation of any of said key levers and restorable to said initial position only upon release of the operated key lever, a pivotally mounted bail oscillatable through a blocked position by said selector mechanism when its clutch is engaged, disengaging means on said bail operable to hold the clutch of the selector mechanism disengaged when said bail is in the blocked position, blocking means on the universal bar to hold said bail in its blocked position when the universal bar is in its initial position, non-repeat means pivotally mounted upon said universal bar and movable with said universal bar to a position for blocking a second oscillation of said bail when said universal bar is in its secondary position, latch means on said non-repeat means operable when said universal bar is in its secondary position, an assurance control means operable to pivot said non-repeat means to a non-blocking position, and means on said assurance control means to engage said latching means on said non-repeat means to hold said assurance control means in a position wherein said assurance means is ineifective to pivot said'non-repeat means until said assurance means is unlatched by movement of said universal bar to its initial position.

5. In a telegraph machine having a cyclically operable selector mechanism normally held from cyclic operation by having its associated clutch means disengaged, a p1u rality of key levers, a plurality of code bars permutatively set by each of said key levers, a universal bar movable from an initial position to a secondary position by operation of any of said key levers and restorable to said initial position only upon release of the operated key lever, a pivotally mounted bail oscillatable through a blocked position by said selector mechanism when its clutch is engaged, disengaging means on said ball operable to hold the clutch of the selector mechanism disengaged when said bail is in the blocked position, blocking means on the universal bar to hold said bail in its blocked position when the universal bar is in its initial position, non-repeat means operable to move into a position to block a second oscillation of said bail when said universal bar is in its secondary position, latching means on said non-repeat means, and an assurance control means biased to a first position to block said non-repeat means against movement to a bail blocking position when said universal bar is in its secondary position and movable by said bail to a position wherein said assurance control means is latched by said latching means in a position to be ineffective to block said non-repeat means until unlatched by movement of said universal bar to its initial position, whereby said non-repeat means blocks a second oscillation of said bail when only a single key lever has been operated during a selector mechanism cycle and whereby said assurance control means blocks movement of the non-repeat means to its bail blocking position when a plurality of key levers have been operated during a selector mechanism cycle.

References Cited in the file of this patent UNITED STATES PATENTS 2,272,420 Miller et al Feb. 10, 1942 2,345,137 Long Mar. 28, 1944 2,754,364 Kleinschmidt et al July 10, 1956 

